Temporary exhaust system

Okay, okay, jeez, I wasn't that set on it anyway. First of all, I'm not actually "breaking in" a fully rebuilt engine; I'm swapping heads, intake, and cam and just need to break in the cam/lifters. I guess I'm just overly worried that if I use any of the stock components my car will be really slow. Before my timing set made ground beef of itself I was always really pissed off and disappointed with how slow it was (wouldn't pull past 3500 RPM and couldn't even chirp one tire) and how quiet it was (my friend's old VW Bug was louder). I am going to be really, really pissed if when I'm finished with everything the car won't be a street beast compared to its former self. This is my first and only car and it's already been over a month since I've had to park the car in my garage and bum rides off my friends and occasionally use my family's minivan to run errands.